BS-EN-212 pdf free download
BS-EN-212 pdf free download.Wood preservatives — General guidance on sampling and preparation for analysis of wood preservatives and treated timber.
5.1.3 Choice of materials for sample container and sampling devices It is essential in all cases that the sampling devices and the sample container and its closure be made from material which is inert to the particular preservative under investigation. NOTE 1 Polyethylene containers should not be used for hydrocarbon solvents. Glass containers are recommended. NOTE 2 Glass containers should not be used for fluorine and boron based preservatives. Containers of polyethylene are recommended. 5.1.4 Marking and storage of samples All sample containers should be clearly and permanently labelled as to their contents. All samples should be stored in their containers in a cool, dark place prior to analysis. 5.2 Sampling of solid preservatives 5.2.1 Sampling device A suitable sampling device for the purpose of sampling the preservative in a drum is a sampling spear of internal diameter approximately 30 mm and sufficiently long to reach the bottom of the drum. 5.2.2 Procedure (see Figure 1) Before sampling, mix the contents of the drum as thoroughly as possible. Take great care to minimize the moisture picked up by the sample during the sampling, mixing and reducing processes. Using the sampling device, take five samples, one from the centre of the drum and the other four from points on a pair of diameters at right angles to each other, which are mid-way between the centre and the side of each drum selected for testing (operation A). Ensure that the sampling spear reaches to the bottom of the drum. Combine the five samples in a clean, dry, airtight container (operation B). If necessary, grind the whole of the bulk sample to pass a test sieve of nominal aperture size 2,00 mm, ensuring that no residue is left on the sieve. NOTE To ascertain the homogeneity of the contents of a drum, individual spear samples can be analysed.5.3 Sampling of preservatives in paste form 5.3.1 Sampling device A suitable device is a wide-mouthed sampling can of about 500 ml capacity fitted with a long, stiff handle so that it can be submerged in the material to be sampled. It should also carry a removable lid to which a second stiff handle or cord is attached, so that when the can is immersed in the paste the lid can be removed, allowing the can to fill. A stout, steel, rod, suitable for stirring the paste is also required. 5.3.2 Procedure Thoroughly mix the preservative in each container before the samples are taken. Displace any settled material from the base of the container using the stirring rod. Re-close the container and homogenize the contents by mechanical agitation. Re-open the containers and test the contents for uniformity by probing with the steel rod. Continue alternate stirring, shaking and rolling until the contents are of a homogeneous consistency. Take three samples from each container with the sampling can, one from just below the surface of the preservative, the second at a position about halfway between the surface and the base of the container and the third from near the base. Pour the three samples from each container into a clean glass or plastic container and mix together. NOTE Should it prove impossible to homogenize the mixture it is necessary to dissolve or disperse the whole contents of the container and take aliquot portions for analysis. 5.4 Sampling of liquid preservatives 5.4.1 Sampling device A suitable sampling device consists of a thick-walled glass tube of about 1 0 mm internal diameter, cut to a length suitable for extracting the treatment solution to a depth of about two thirds of the height of the container from the top. BS-EN-212 pdf download.
